STOMACH-CANCER AFTER PARTIAL GASTRECTOMY FOR BENIGN ULCER DISEASE

We followed for 25 to 33 years 6459 patients who had undergone partial gastrectomy for benign ulcer disease to determine the incidence of stomach cancer. The overall risk was no different from that among sex- and age-matched controls from the Swedish Cancer Registry (standardized incidence ratio = 0.96; 95 percent confidence limits, 0.78 and 1.16). However, when the patients were classified according to the duration of follow-up after operation, sex, surgical procedure, diagnosis at the time of operation, and age at operation, differences in risk were observed between the subgroups. After adjustment for potential confounding variables, the average adjusted risk increased 28 percent (adjusted standardized incidence ratio = 1.28; 95 percent confidence limits, 1.11 and 1.49) for each successive five-year interval after operation. The adjusted risk was greater among women than men (adjusted standardized incidence ratio = 1.96; 95 percent confidence limits, 1.18 and 3.24). Patients who had undergone a Billroth I anastomosis had a lower crude risk, both overall (standardized incidence ratio = 0.40; 95 percent confidence limits, 0.20 and 0.71) and after we controlled for other confounding variables (adjusted standardized incidence ratio = 0.27; 95 percent confidence limits, 1.45 and 3.35). Risk decreased with increased age at operation. Between successive strata of age at operation (< 39, 40 to 49, 50 to 59, and .gtoreq. 60 years of age), the adjusted risk decreased on the average by about half (adjusted standardized incidence ratio = 0.52; 95 percent confidence limits, 0.41 and 0.66).